Solution:

Time : 3.21 hours

To solve the problem
(1/X) + (1/Y) = 1/T
After Solving
14/45 = 1/T
Thus T = 45/14 = 3.21

Solution:

50%

Explanation:
n (a^b) = n(a) + n(b) - n (a v b)
=> 0.75 + 0.55 - 0.8
=> 0.5 which is equal to 50%
Thus 50% students answered both the questions correctly

Solution:

88

Explanation:
Sum of 4 tests = 78*4 = 312
Sum of 5 tests = 80*4 = 400
Thus, Fifth test score = 400 - 312 = 88

Solution:

48%

Explanation:
200*57% = 114
300*42% = 126
Thus total germinated seeds = 240
Total planted seeds = 500
Percentage of germinated seeds = 240/500 = 48%

Solution:

6ft

Explanation:
Given volume = 36, height = 4ft
Volume of Cylinder = Pi*square r*h
36 = Pi*squarer*4
Square r = 9
R = 3
Thus the radius of the cylinder = 3ft
Diameter = 2*radius = 6ft

Solution:

15

Explanation:
30/1 = t/a ---- Current teenagers to adults ratio
t+50/a+5 = 25/1 ---- Future teenagers to adults ratio
Solving the first equation for t gives t = 30t.
Substitute this value of t into the second equation, and solve for t.
t+50/a+5 = 25/1
30a + 50 = 25a + 125 multiply both sides by a+5
5a = 75 simplify by subtraction
a = 15

Solution:

110-130

Explanation:
Total students = 200
Studying neither Chemistry nor Biology =30
Chemistry = 130
Bio = 130
Maximum common = Minimum of the two = 130
If neither = 30
Then common = 150 + 130 + 30 - 200 = 110
Range is 110-130

Solution:

2:3

Explanation:
100-60 = 40
Ration => 40:60 = 2:3

Solution:

25 seconds

Explanation:
Machine X manufactures 120/40 = 3 microchips every second
Machine Y produces 100/20 = 5 microchips per second
Combined productivity per second = 3 + 5 = 8
Hence seconds required to manufacture 200 bolts = 200/8 = 25 seconds

Solution:

816

Explanation:
With an interest rate of 8% for half year
10000x 8/100x1/2=400
We get Rs. 400
For the next year, the interest will be there on your investment of 10000 and also on the interest of Rs. 400
Thus we get another Rs. 400 + Interest on 400 - @8% for half year = 400+(400x8/100x1/2)
400+400+16=816

Solution:

11x/y

Solution:

She will retire in 2005

Explanation:
To retire Julianne must accumulate 70 in total
At the joining she already have 32 points and every year after that will add two more points to 32, one for her age and one for the employment.
Thus, 32 + 2*(number of years) = 70
Number of years = 19
1986+19 = 2005
Which means she will retire in 2005

Solution:

The argument of Chris Evans is quiet flawed as he fails to differentiate between purchasing and consuming.

Solution:

Assume that the subscribers on 1 Jan 1995 were X
15% of X = 15/100*(X)
(X) + [15/100*(X)] = 45 ---- as there is 15% increase from 1995 to 1997
X=39.13

Solution:

420

Explanation:
L.C.M of (1,2,3,4,5,6,7)=2*2*3*5*7=420

Solution:

14.4 cms

Explanation:
Area of Square = Area of Rectangle
Side square = l*b
6 square = X(2.5)
36 = X(2.5)
X=14.4 cms.

Solution:

6.67%

Explanation:
Originally in 10000 gallons of liquid, we have 5% potassium chloride which is equal to 500 gallons
Now 2500 gallons evaporated
10000-2500 = 7500
Required percentage = (500/7500) * 100 = 6.67 %

Solution:

4 dozens

Explanation:
Since half of the total were sold by noon, we are left with twenty dozen pastries
Out of that, 80% were sold till the closing which leaves us with four dozens of pastries.

Solution:

3X/200

Explanation:
The price at which each micro SD card was bought = X/100
Now each card was sold with 50% profit
Thus, cost of each battery when sold = X/100 + X/100*50/100
= X/100 + X/200
= 3X/200

Solution:

7150 = 2*5*5*11*13
Thus only four distinct numbers are present that are below 100.